Flexible-shaft synchronizing gear



Aug. 12, 1924; 1,504,713

H. O. RUSSELL ET AL FLEXIBLE SHAFT sYNcHRoNlzING GEAR Filed April 18, 1922 Patented Aug. i2, 3924i.

HERBERT 0. RUSSELL, OF DETROIT, MICHIGAN, AND CHARLES LEIGH PAULS, OF

v DAYTON, OHIO.

FLEXIBLE-SHAFT SYNCI-IRONIZING GEAR.

Application led April 18, 1922. Serial No. 555,399.

tween the blades of an aircraft propellerV without striking them. The object Vofthe invention is to produce a synchronizing gear of extremely light and simple construction, reliable in operation, containing a minimum number of parts and capable of more universal installation than any other known means at present in use, for the purpose of synchronizing an aircraftmachine gun with` the blades of the propeller. l

lVith the above and other objects in view,

the invention consists of the novel construction, combination and arrangement herein fully described, illustratedand claimed.

In the accompanying drawings:

Figure l is a sectional view of the synchronizing gear.

Figure 2 is a section taken at av right angle to Figure l.

The synchronizing gear contemplated in this invention is driven by a iieXible driv-V ing shaftvl in turn driven by the Vengine either at propeller speed or at some suitable direct ratio of the propeller speed, said flexible shaft running to the housing Q of a trigger motor attached to the side of the machine gun. l

The iieXible shaft l splines or its otherwise connected to the driving shaft 3 of t-he trigger motor which shaft is mounted in ball bearings in the housing of the trigger motor as shown in Figure l. Attached to the shaft 3 by means-of opposing serrated discs t and 1L and a clamping bolt 5 is a cam 6. The cam 6 operates against the sear slide operating plunger 7 which in turn operates the sear slide of the gun. At every rotation of the shaft 3, the humps upon the cam 6 work against the plunger 7 and pus-h. the latter outwardly, downwardly as shown in Fig. 1to gun firing position,

in case the bolt of the machine gun is in the proper position.

The function of the serrated discs is to permit adjustment of the position of the humps of the cam with reference to the shaft in order t-o time the firing of the machine gun properly with reference to the position of the propeller blades.

The operation of the plunger 7 which fires the machine gun is, controlled by a Bowden wire control 7 connected to a control plunger 8 working through the side of the trigger motor as shown in Figure 2. When the control plunger 8 is in its forward position as is shown in Figure l it forces the sear slide operating plunger downwardly and prevents it from coming in contact with the cam 6 and thus being operated. The mechanism of the plunger 7 is similar to that of the slide in the Nelson gun control trigger motor for the Browning gun. Upon the control plunger being withdrawn from contact with the sear .slide operating plunger, the latter is moved inwardly toward the cam, upwardly as shown in Figure l by a spring 9 until it is in operative relation to the cam 6 and thereafter the sear slide operating plunger is again operated by the cam, firing the mechanism. l/Vhen the sear slide operating plunger is in the outward position, or downward, as shown in Figure l, the machine gun bolt Comes home after the last shot is fired, and the sear slide 10 of the machine gun strikes against the side of the sear slide operating plunger 7 at ll, slightly displacing it into a recess l2 and rotating Vit out of the normal path of the sear slide of t-he gun, so that thereafter it is impossible for the gun to be fired until the control plunger 8 is withdrawn and the sear slide operating plunger 7 moved back to its operative position by the spring 9. lVhen the sear slide operating plunger 7 is thus again straightened out, the end thereof4 will eect the firing of the gun.

Tt will be noted'that the sear slide operating plunger 7 is shown in the down position with its lower end Vprotruding through the side plate of the gun. This plunger is held in this position by the control plunger 8, at all times when the gun is not firing. This is made possible by the clearance cut l2 because of the fact that as the bolt goes to the rear, the cooking lever cocks the firing pin 13 allowing the sear slide l() to slide over into place. As the bolt returns to the forward position, the sear slide strikes the sear slide operating plunger 7 at a point indicated at 1l. This forces the sear slide operating` plunger forward into the clearance l0, in which position it stands until the control plunger 8 is removed from above the sear slide operating rplunger 7 allowing the spring 9 to force the plunger up into contact with the trigger motor cam 6. The trigger motor spring 9 is located in such a position as to force the lower end of the sear slide operating plunger over into alignment with the: gun scar slide as it moves upward. The trigger motor cam 6 having two lobes and being in constant rotation driven by a flexible shaft from theengine, causes two cycles of the triggermotor plunger per revolution of v:the propeller.

The Cycle of function described is known as the single shot Vfeature of this invention7 inasmuch as it causes the gun to be fired at the same position in the rotation of the cam in every cycle of its movement. rfhis is due to the fact that should the bolt be returning to its forward position and the sear slide operating plunger be on its downward stroke at the same instant, the sharp edge at the rear of the Asear slide operating plunger or will not ride the top face of the seal* slide. Should vthe searslide be'slightly in advance of the movement of the plunger, the plunger will depress the slide and fire the gun at exactly the'same instant as it would lire in any other cycle. But `should the plunger be slightly in advance ofthe sear slide of the gun, itwill be tilted forward and fail to fire the gun. The `next cycle of the cam would allow'the plunger to'rise. The trigger motor spring E would align the plunger and the sear slide of the gun 'and fire the gun at the next cycle of the cam F.

Another distinctive feature of the synchronizing gear above describedvresides in the vfact that the flexible shaft l operates continuously and that firing is started and stopped by moving the slide 7 into and out of operative contact with the cam 6. Heretofore the firing operation has been controlled by starting and stopping the flexible shaft which operates the trigger motor, requiring a much stronger and heavier shaft and amore complicated mechanism to insure the instantaneous starting and stopping of the machine gun.

Having thus described our invention, we claim:

l. In a synchronizing gear for machine guns, an engine driven shaft terminatingat one end in a serratedY disc, a cam shaft terminating at one end in a serrated disc adapted to mesh with said first named disc to eEect the adjustment of said cam shaft in shaft, and clamping means to hold said faces against relative movement.

3. Inj synchronizing gear for machine guns, a trigger `rmotor embodying a housing, a driven shaft, a cam on said shaft, and a Sear slide operating plunger adapted to be actuated by said cam, and a control means for moving said scar slide operating plunger into and out of operative position.

il. In synchronizing gear for machine guns, a trigger motor embodying a housing, a driven shaft, a cam von said shaft and a sear slide 'operating plunger adapted to be actuated by-said cam, and a manual control means for moving said sear slide operating plunger into and out of operative position.

5. In a synchronizing gear for machine guns, a trigger motor embodying a housing, a driving shaft, a cam on said shaft, a sear slide operating plunger adapted to be actuated by said cam, control means for said sear slide operating plunger embodying means for 'depressing the same to a position where it will be out of contact with said cam.

v6. In a synchronizing gear for machine guns, a trigger motor embodying a housing, a driving shaft, a cam on said shaft, a sear slide operating plunger adapted to be actuated by said cam, control means for said sear slide operating vplunger embodying means for depressing the same into the path of the sear slide of the gun with which it is to be used. l

7. In Va synchronizing gear for machine guns, a trigger motor embodying a housing, a drivingshaft, a camon said shaft, a sear slide operating plunger adapted to be actuated by said cam, control means for said sear slide operating plunger embodying means for depressing the same to a position where it will be out of contact with said cam and into the path of the sear slide of the gun ,in connection with which it is to be used.

8. In synchronizing Oear for machine guns, a trigger motor embodying a housing, a driving shaft, a cam on said shaft, and a Sear-operating slide adapted to be moved out of operativeposition when struck by the sear slide ofthe gun.

9. In synchronizing gear for machine guns, a trigger motor embodying a housing, a driving shaft, a cam on said shaft. and a lil() Sear-operating slide adapted to loe moved out of operative position When struck by the seal slide of the gun, said senr-operating slide being partially rotatable.

l0. In synchronizing gear for machine guns, a trigger motor embodying a housing, a driving shaft, a, cam on said shaft, and a Sear-operating slide adapted to be moved out of operative position When struck by the Sear slide of Jthe gun, and manually-oontrolled means for holding said sea1'opei'ating slide in a projected position.

In testimony whereof We affix oui' signatures.

HERBERT O. RUSSELL. CHARLES LEIGH PAULUS. 

